#box {
    width: 600px;
    height: 200px;
    border: 2px solid #000;
    border-radius: 5px;
    padding: 10px;
}
h2 {
    display: inline-block;
}
#btn {
    display: inline-block;
    border: 1px solid skyblue;
    border-radius: 25px;
    outline: none;
}